The focus of this document is on providing a reference for writing C#. It includes naming, structural and formatting conventions as well as best practices for writing clean, safe and maintainable code. Many of the best practices and conventions apply equally well to other languages.
It's fine to use them, of course. Just be aware that the lifetime of each using is the entire method. If you stick to shorter methods without or with limited side-effects, then this won't be a problem. Just make sure that you're not allowing the lifetime of an IDisposable be extended unnecessarily because you didn't close it off with braces. If this is happening, then you probably have a method that's doing two things anyway and you can take this as a hint that you should split the method, possibly using local functions to determine the disposable's lifetime.
Notes
It's fine to use them, of course. Just be aware that the lifetime of each using is the entire method. If you stick to shorter methods without or with limited side-effects, then this won't be a problem. Just make sure that you're not allowing the lifetime of an
IDisposablebe extended unnecessarily because you didn't close it off with braces. If this is happening, then you probably have a method that's doing two things anyway and you can take this as a hint that you should split the method, possibly using local functions to determine the disposable's lifetime.